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This document details the design of a Passive UHF RFID Temperature Sensing Antenna Tag, integrated into biocompatible material, to incorporate within a brain surgical prosthesis. This wireless and non-invasive RFID device allows temperature monitoring, affording valuable clinical control of the patient?s status. A material characterization, RFID Tag design, manufacturing and verification process of the RFID part and Sensor capabilities have been performed. In default of the accuracy calibration sensor and the need to enhance the industrial process, this innovation assures to revolutionize the patients? status monitoring. The RFID Sensing Tag provides a diagnosis and vital control tool helping health professionals, improving substantially the preventive examination to reduce the required time of hospitalization, recovery, and rehabilitation due to this new generation of Implants RFID., Este documento detalla el diseño de una antena Tag Pasiva RFID para UHF con sensor de temperatura, integrado en medio de material biocompatible, incorporado dentro de una prótesis quirúrgica cerebral. Este dispositivo RFID inalámbrico y no invasivo permite monitorizar la temperatura, obteniendo un control del estado clínico del paciendo de alto valor. Se han llevado a cabo procesos de caracterización de materiales, diseño de un Tag RFID, fabricación y verificación de la parte de RFID y del sensor de temperatura. A falta de la calibración precisa del sensor y la necesidad de mejorar el proceso industrial, esta innovación asegura revolucionar la monitorización del estado del paciente. El Tag RFID con sensor aporta una herramienta de diagnóstico y control vital ayudando al personal médico, mejorando de forma significativa la evaluación preventiva reduciendo los tiempos necesarios de hospitalización, recuperación y rehabilitación debido a esta nueva generación de implantes RFID., Aquest document detalla el disseny d'una antena Tag RFID Passiva per UHF amb sensor de temperatura, integrat entremig de material biocompatible, incorporat dins d'una pròtesi quirúrgica cerebral. Aquest dispositiu RFID sense fils i no invasiu permet monitoritzar la temperatura, obtenint un control de l'estat clínic del pacient d'alt valor. S'han dut a terme processos de caracterització de materials, disseny d'un Tag RFID, fabricació i verificació de la part d'RFID i del sensor de temperatura. A falta de la calibració precisa del sensor i la necessitat de millorar el procés industrial, aquesta innovació assegura revolucionar la monitorització del estat del pacient. El Tag RFID amb sensor de temperatura aporta una eina de diagnòstic i control vital ajudant al personal mèdic, millorant de forma significativa l'avaluació preventiva reduint els temps necessaris d'hospitalització, recuperació i rehabilitació a causa d'aquesta nova generació d'implants RFID.

El propósito del presente trabajo pasa por analizar la permitividad y el factor de pérdidas tanto del polietile-no de alta densidad (HD-PE), como del compuesto de matriz polimérica (HD-PE)reforzado con neumáticos fuera de uso (Ground Tire Rubber: GTR), con el fin de demostrar su viabilidad como material aislante eléc-trico (dieléctrico). Como es sabido, la incorporación de negro de humo en un polímero permite modificar su conductividad, y cómo el GTR lleva un porcentaje significativo de negro de humo, algunas de las pro-piedades eléctricas del nuevo compuesto cambiaran significativamente con respecto al polímero que es altamente aislante. El estudio se centrará, en un rango de frecuencias y temperaturas aptas para demostrar la viabilidad de este nuevo compuesto en usos indus-triales, enfocándolo principalmente en el análisis de la Permitividad, ya que es una propiedad clave para los condensadores. No obstante, también se caracterizará el comportamiento térmico y estructural, haciendo especial énfasis en el rango de trabajo del condensador (por debajo de los 100ºC). Finalmente, con el análisis estructural, se pretende contribuir al conocimiento de estos materiales compuestos provenientes de reciclaje, y así, aprovechar su potencial de reutilización, haciéndolos atractivos para las empresas interesadas en su relación rendimiento/precio., The purpose of this work is to analyze the permittivity and the loss factor of both high-density polyethylene (HD-PE), as well as the polymer matrix composite (HD-PE) reinforced with end-of-life tires (Ground Tire Rubber: GTR), in order to demonstrate its viability as electrical insulating material (dielectric). As is known, the incorporation of carbon black in a polymer allows its conductivity to be modified, and since the GTR carries a significant percentage of carbon black, some of the electrical properties of the new compound will change significantly with respect to the polymer that is highly insulating. The study will focus on a range of frequencies and temperatures suitable to demonstrate the viability of this new composite in industrial uses, focusing mainly on the analysis of Permitivity, since it is a key property for capacitors. However, the thermal and structural behavior will also be characterized, with special emphasis on the capacitor working range (below 100ºC). Finally, with the structural analysis, it is inten-ded to contribute to the knowledge of these composite materials from recycling, and thus, take advantage of their potential for reuse, making them attractive for companies interested in their performance/price ratio., El propòsit del present treball passa per analitzar la permitivitat i el factor de pèrdues tant del polietilè d'alta densitat (HD-PE), com del compost de matriu polimèrica (HD-PE) reforçat amb pneumàtics fora d'ús (Ground Tire Rubber: GTR ), amb la finalitat de demostrar la seva viabilitat com a material aïllant elèctric (dielèctric). Com és sabut, la incorporació de negre de fum en un polímer permet modificar la seva conductivitat, i com el GTR porta un percentatge sig-nificatiu de negre de fum, algunes de les propietats elèctriques del nou compost canvien significativament respecte del polímer, que és altament aïllant. L'estudi es centrarà, en un rang de freqüències i temperatures aptes per demostrar la viabilitat d'aquest nou compost en usos industrials, enfocant principalment en l'anàlisi de la Permitivitat, ja que és una propietat clau per als condensadors. No obstant això, també es caracteritzarà el comportament tèrmic i estructural, fent especial èmfasi en el rang de treball d’un condensador (per sota dels 100 º C). Finalment, amb l'anàlisi estructural, es pretén contribuir a el coneixement d'aquests materials compostos provinents de reciclatge, i així, aprofitar el seu potencial de reutilització, fent-los atractius per a les empreses interessades en la seva relació rendiment/preu., Peer Reviewed, Postprint (published version)

Study of the characteristics of the different layers of the EWOD lens and the manufacturing method for each one of them. In addition, the hydrophobic or hydrophilic behavior of a liquid is studied when it is deposited on the lens and a certain voltage is applied to it. All work done in a clean room., Estudio de las características de las diferentes capas de la lente basadas en la electrohumectación del dieléctrico y el método de fabricación de cada una de ellas. Además, se estudia el comportamiento hidrofóbico o hidrofílico de un líquido cuando se deposita sobre la lente y se le aplica un determinado voltaje. Todo el trabajo realizado en una sala blanca., Estudi de les característiques de les diferents capes de la lent basades en l'electrohumectació del dielèctric i el mètode de fabricació de cadascuna. A més, s'estudia el comportament hidrofòbic o hidrofílic d'un líquid quan es diposita sobre la lent i se li aplica un voltatge determinat. Tota la feina feta en una sala blanca.

The present study demonstrates the reduction in the dielectric loss at room temperature from 0.149 to 0.027 in the composite of (NdFeO3)0.1−(Ba0.7Sr0.3TiO3)0.9 as compared to the undoped Ba0.7Sr0.3TiO3 and correlates with the charge compensation due to the ionic substitutions for both A site (NdBa) and B (FeTi) site generated excess electrons, localized hole states and robust oxygen vacancies (VO) along with different cationic oxidation states. The VO mediated F center charge transfer mechanism i.e., bound magnetic polaronic behaviour and defect complex generated between acceptors and ionized VO reduce electrical conductivity and loss factor. The presence of weak ferromagnetism in the M-H loop reconfirms the F center exchange mechanism in mixed phase symmetry. The activation energy calculated from impedance spectroscopy, electrical modulus and electrical conductivity analysis supports the presence of doubly ionized VO. Further, density functional theory based first principle calculation manifests that the impurity induced depopulation of valence band edge electrons into a single spin up channel which distorts TiO6 octahedra with fluctuating bond length and Ti 3deg orbital splitting observed in decomposed density of states for accommodating excess electrons. These trapped and accommodated electrons reduce the effective electron concentration which in turn decreases the electrical conductivity and loss factor., QC 20220810

A new theoretical model for the dielectrophoretic (DEP) fabrication of single-walled carbon nanotubes (SWCNTs) is presented. A different frequency interval for the alignment of wide-energy-gap semiconductor SWCNTs is obtained, exhibiting a considerable difference from the prevalent model. Two specific models are study, namely the spherical model and the ellipsoid model, to estimate the frequency interval. Then, the DEP process is performed and the obtained frequencies (from the spherical and ellipsoid models) are used to align the SWCNTs. These empirical results confirm the theoretical predictions, representing a crucial step towards the realization of carbon nanotube field-effect transistors (CNT-FETs) via the DEP process based on the ellipsoid model. © 2020, The Author(s).

The purpose of the present research is to obtain waste of polymeric composite as an insulator capacitive application. Rubber materials, once they end their useful life, may be difficult to reuse or recycle. At present, research only uses one tire recycling method, which involves grinding and separating steel and fibers from vulcanized rubber, and then using the rubber particles for industrial capacitors. The methodology for this research is to compare the permittivity (e' and e¿) between high-density polyethylene (HDPE) and the polymer matrix compound, consisting of an HDPE polymeric matrix blended with end-of-life tire particles (ground tire rubber (GTR)), to analyze the feasibility of using such tires as electrically insulating materials (dielectrics). The incorporation of carbon black in the GTR compounds modifies conductivity; GTRs carry a significant amount of carbon black, and therefore some electrical properties may change significantly compared to highly insulating polymer substrates. The performed experimental study is based on a dynamic electric analysis (DEA) test developed in the frequency range of 10-2 Hz to 3 MHz and at different temperatures (from 35 to 70 °C) of different samples type: HDPE neat and HDPE compounds with 10%, 20% and 40% of GTR loads. A sample’s electrical behavior is checked for its dependence on frequency and temperature, focused on the permittivity property; this is a key property for capacitive insulators and is key for examining the possible applications in this field, for HDPE + GTR blends. Results for the permittivity behavior and the loss factor show different electrical behavior. For a neat HDPE sample, no dependence with frequency nor temperature is shown. However, with the addition of 10%, 20%, and 40% amount of GTR the HDPE compounds show different behaviors: for low frequencies, interfacial polarization relaxation is seen, due to the Maxwell–Wagner–Sillars (MWS) effect, performed in heterogeneous materials. In order to ana, Peer Reviewed, Postprint (published version)

Los vidrios y cristales desordenados han sido objeto de debate debido a su comportamiento anormal en sus propiedades dieléctricas y termodinámicas. En el siguiente trabajo, se ha estudiado un conjunto de dos muestras que consisten en cristales orientacionalmente desordenados pero ordenados traslacionalmente para analizar sus modos vibratorios excesivos con respecto al modelo de Debye, también llamado Boson Peak, a diferentes temperaturas. Los dos materiales considerados son el pentacloronitrobenceno (PCNB) y el 1-fluoroadamantano (1-FAda) y se analizarán mediante un sistema de time-domain-spectroscopy THz (THz-TDS). Ambos presentan anomalías vítreas y nuestros resultados muestran cómo una cantidad mínima de desorden en las redes ordenadas traslacionalmente revela la presencia de fonones ópticos de baja energía (vibraciones colectivas) que se hibridan con los fonones acústicos ordinarios, dando sitio a un exceso de estados vibratorios que produce la emergencia de Boson Peak., Els vidres i cristalls desordenats han estat objecte de debat a causa del seu comportament anormal en les seves propietats dielèctriques i termodinàmiques. En el següent treball, s'ha estudiat un conjunt de dues mostres que consisteixen en cristalls orientacionalment desordenats però ordenats translacionalment per a analitzar el seu excés de modes vibracionals respecte al model de Debye, també anomenat Boson Peak, a diferents temperatures. Els dos materials considerats són el pentacloronitrobenzè (PCNB) i l'1-fluoroadamantà (1-FAda) i s'analitzaran mitjançant un sistema de time-domain-spectroscopy THz (THz-TDS). Tots dos presenten anomalies vítries i els nostres resultats mostren com una quantitat mínima de desordre en les xarxes ordenades translacionalment revela la presència de fonons òptics de baixa energia (vibracions col·lectives) que s'hibriden amb els fonons acústics ordinaris, donant lloc a un excés d'estats vibracionals que produeix la emergència de Boson Peak., Disordered crystals and glasses have been subject of debate because of its abnormal behavior on their dielectric and thermodynamical properties. In the following work a set of two samples consisting on orientationally disordered but translationally ordered crystals have been studied in order to analyze their excess vibrational modes with respect to the Debye model, also called Boson Peak, at different temperatures. The two materials considered are Pentachloronitrobenzene (PCNB) and 1-Fluoroadamantane (1-FAda) and will be analysed by means of with a THz-Time Domain Spectroscopy system (THz-TDS). They both present glassy anomalies and our results show how a minimal amount of disorder in the translationally ordered lattices gives out the presence of low-energy optic phonons (collective vibrations) that hybridize with the ordinary acoustic phonons, producing an excess of vibrational states that gives rise to the Boson Peak.

The main objective of this project is to design, fabricate and test a resonator capable of measuring the required properties of different dielectric samples in the microwave region for a temperature range of 20 – 100 K that will be later used to characterize the HTS-CCs. Results for Rutile and Strontium Titanate are presented., L’objectiu principal d’aquest projecte és dissenyar, fabricar i provar un ressonador capaç de mesurar les propietats requerides de diferents mostres dielèctriques en la regió de microones per a un rang de temperatura entre 20 - 100 K que posteriorment s’utilitzarà per caracteritzar els HTS-CCs. Es presenten resultats per al Rútil i Titanat d’Estronci., El objetivo principal de este proyecto es diseñar, fabricar y probar un resonador capaz de medir las propiedades requeridas de diferentes muestras dieléctricas en la región de microondas para un rango de temperatura entre 20 - 100 K que luego se utilizará para caracterizar los HTS-CCs. Se presentan resultados para el Rutilo y Titanato de Estroncio.

In this paper, the utilization of high dielectric constant resonator as a passive element for design of filter in the range of Ku band is investigated. The design is based on a new kind of dielectric resonator fabricated with a commercial high dielectric constant EPOXY paste. The design is based on a microstrip line periodically loaded with a new kind of dielectric resonator fabricated with a commercial high dielectric constant Epoxy paste compatible with serigraphy and screen printing technology., Postprint (published version)

In this paper, an improved 4H-SiC U-shaped trench-gate metal-oxide-semiconductor field-effect transistors (UMOSFETs) structure with low ON-resistance (R ON ) and switching energy loss is proposed. The novel structure features an added n-type region, which reduces ON-resistance of the device significantly while maintaining the breakdown voltage (V BR ). In addition, the gate of the improved structure is designed as a p-n junction to reduce the switching energy loss. Simulations by Sentaurus TCAD are carried out to reveal the working mechanism of this improved structure. For the static performance, the ON-resistance and the figure of merit (FOM = V BR 2 /R ON ) of the optimized structure are improved by 40% and 44%, respectively, as compared to a conventional trench MOSFET without the added n-type region and modified gate. For the dynamic performance, the turn-on time (T ON ) and turn-off time (T OFF ) of the proposed structure are both shorter than that of the conventional structure, bringing a 43% and 30% reduction in turn-on energy loss and total switching energy loss (E SW )., QC 20190710

The miniaturization and integration of electronic devices demand the development of more excellent materials with multifunction as well as novel structural designs. In this dissertation, based on spinel ferrite, the low-loss magnetodielectric ceramics with coexisted dielectric and magnetic properties have been systematically investigated through tuning the chemical constituent and microstructure, or optimizing experimental approach. Besides, the epitaxial garnet ferrite thin films have been also fabricated by adopting a new deposition method with a radio frequency magnetron sputtering system. The main research topics in this dissertation1 include the magnetodielectric properties in (1-y)(Mg0.95Zn0.05)2TiO4-yMg0.95Zn0.05Fe2O4(MZT-MZF) ceramics, the magnetic anisotropy in Co1.1Fe1.9O4 (CFO) laminated ceramics, the magnetodielectric properties in mixed cobalt-rich Co1.1Fe1.9O4/Ba(Zr0.085Ti0.915)O3 (CFO/BZT) laminated composites, and the low-loss magnetic properties in epitaxial yttrium iron garnet thin films. By designing new composites constitutes and new fabrication methods, the physical properties of both spinel and garnet materials were immensely improved, providing valuable guiding significance for design and fabrication of novel multifunctional electronic components and devices. As spinel ferrites, both Mg2TiO4 and MgFe2O4 have similar cubic structures, which is the precondition to form a solid solution. Also, an appropriate doping of Zn2+ ions can considerably improve the physical properties of these two ferrites. By adding 5% molar Zn2+ ions, the sintering temperature of the (1-y)(Mg0.95Zn0.05)2TiO4-yMg0.95Zn0.05Fe2O4

The miniaturization and integration of electronic devices demand the development of more excellent materials with multifunction as well as novel structural designs. In this dissertation, based on spinel ferrite, the low-loss magnetodielectric ceramics with coexisted dielectric and magnetic properties have been systematically investigated through tuning the chemical constituent and microstructure, or optimizing experimental approach. Besides, the epitaxial garnet ferrite thin films have been also fabricated by adopting a new deposition method with a radio frequency magnetron sputtering system. The main research topics in this dissertation1 include the magnetodielectric properties in (1-y)(Mg0.95Zn0.05)2TiO4-yMg0.95Zn0.05Fe2O4(MZT-MZF) ceramics, the magnetic anisotropy in Co1.1Fe1.9O4 (CFO) laminated ceramics, the magnetodielectric properties in mixed cobalt-rich Co1.1Fe1.9O4/Ba(Zr0.085Ti0.915)O3 (CFO/BZT) laminated composites, and the low-loss magnetic properties in epitaxial yttrium iron garnet thin films. By designing new composites constitutes and new fabrication methods, the physical properties of both spinel and garnet materials were immensely improved, providing valuable guiding significance for design and fabrication of novel multifunctional electronic components and devices. As spinel ferrites, both Mg2TiO4 and MgFe2O4 have similar cubic structures, which is the precondition to form a solid solution. Also, an appropriate doping of Zn2+ ions can considerably improve the physical properties of these two ferrites. By adding 5% molar Zn2+ ions, the sintering temperature of the (1-y)(Mg0.95Zn0.05)2TiO4-yMg0.95Zn0.05Fe2O4

The miniaturization and integration of electronic devices demand the development of more excellent materials with multifunction as well as novel structural designs. In this dissertation, based on spinel ferrite, the low-loss magnetodielectric ceramics with coexisted dielectric and magnetic properties have been systematically investigated through tuning the chemical constituent and microstructure, or optimizing experimental approach. Besides, the epitaxial garnet ferrite thin films have been also fabricated by adopting a new deposition method with a radio frequency magnetron sputtering system. The main research topics in this dissertation1 include the magnetodielectric properties in (1-y)(Mg0.95Zn0.05)2TiO4-yMg0.95Zn0.05Fe2O4(MZT-MZF) ceramics, the magnetic anisotropy in Co1.1Fe1.9O4 (CFO) laminated ceramics, the magnetodielectric properties in mixed cobalt-rich Co1.1Fe1.9O4/Ba(Zr0.085Ti0.915)O3 (CFO/BZT) laminated composites, and the low-loss magnetic properties in epitaxial yttrium iron garnet thin films. By designing new composites constitutes and new fabrication methods, the physical properties of both spinel and garnet materials were immensely improved, providing valuable guiding significance for design and fabrication of novel multifunctional electronic components and devices. As spinel ferrites, both Mg2TiO4 and MgFe2O4 have similar cubic structures, which is the precondition to form a solid solution. Also, an appropriate doping of Zn2+ ions can considerably improve the physical properties of these two ferrites. By adding 5% molar Zn2+ ions, the sintering temperature of the (1-y)(Mg0.95Zn0.05)2TiO4-yMg0.95Zn0.05Fe2O4

Microwave absorbers generally consist of a filler material inside a polymer matrix. The filler contains one or more elements that do most of the absorbing. Absorbers are used in a wide range of applications to eliminate stray or unwanted radiation that could interfere with a system’s operation. Ferrites is the most common shielding material in the development of absorbing composites. However, ferrites are heavy, corrosive, non-biodegradable and expensive. This project investigates the application of oil palm empty fruit bunch fibres (OPEFB) as an alternative to ferrite fillers for microwave absorbing applications with PLA as the host matrix. OPEFB offer various advantages such as low cost, low density, better thermal, insulating properties and biodegradability. Also PLA has significant advantages including ease of fabrication, zero toxicity, biodegradability, high mechanical strength and thermal plasticity. Different compositions of filler were doped and blended to produce OPEFB-PLA and OPEFB-PLA-Fe2O3 composites via Brabender Plastograph EC blending machine operating at 170°C with rotor speed of 50 rpm for 20 minutes. The total mass of each blended composite was 45g and contained 200 μm size OPEFB fibres. The crystalline structure of the composites was analyzed using X-ray diffraction (XRD) machine. The elemental compositions were examined using Scanning Electron Microscopy (SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared (FTIR) techniques. Thermal analyses were carried out using TGA and DTG. The dielectric properties and S-Parameters, were measured using a PNA (N5227) Network Analyzer from 8GHz to 12 GHz for rectangular waveguide and 0.01 GHz to 12 GHz for microstrip at room temperature. The theoretical calculations of the S-Parameters coefficients of the samples were computed using Finite Element Method (FEM) in conjunction with the COMSOL software. The comparison between the measured and calculated scattering parameters was also inves

This paper is orientated for the ones who are interested in solving the heat dissipation issue that occurs in the field of Power Electronics. In high voltage direct current (HVDC) transmissions the use of water as a heat transfer fluid can be inappropriate because of the strong levels of electric tension to which it is subjected. Therefore, in order to continue dissipating heat by means of a fluid (convection), other type of coolants should be used, specifically those which remain inert when subjected to high voltages. That is, dielectric fluids specially designed with good thermal properties for this particular function. The main objectives of this document are the validation of an analytical model that can accurately predict the behaviour of the considered fluid coolants in terms of heat dissipation and pressure drop and to give the reader an overall view on how can different fluid coolants work from a thermal point of view, involving also a comparison with liquid water. The standard cooling system considered consists of a heat source that represents an average Power Electronics chip, an aluminium plate-fin heat sink and the coolant flow that removes the heat from the fins as it travels through the heat sink. The validation of the analytical model was done by comparing it to a numerical one, specifically with simulations made with ANSYS Fluent, the CFD engineering software used world-wide for industry applications. In the first step, liquid water was successfully validated. Therefore, the analysis advanced to the second phase which brought some interesting results for the three dielectric fluid coolants analysed (3M Novec 7500, Galden HT-135 and Fluorinert FC-3283) but not so satisfactorily results for water-glycol (the other fluid studied). From that point, two parallel paths were opened: one for researching why the analytical model did not work for water-glycol as good as for the three dielectric coolants and the other one consisted in the behaviour comparison o, Outgoing

This is the peer reviewed version of the following article: A. M. Hagerstrom, X. Lu, N. M. Dawley, H. P. Nair, J. Mateu, R. D. Horansky, C. A. E. Little, J. C. Booth, C. J. Long, D. G. Schlom, N. D. Orloff, Adv. Mater. Technol. 2018, 3, 1800090. https://doi-org.recursos.biblioteca.upc.edu/10.1002/admt.201800090, which has been published in final form at https://doi.org/10.1002/admt.201800090. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving., Voltage-tunable dielectric materials are widely used for microwave-frequency signal processing. Among tunable dielectric thin films, (SrTiO3)nSrO Ruddlesden–Popper (RP) superlattices have exceptionally low loss at high frequencies. This paper reports the first realization of resonators, a ubiquitous building block of microwave components, fabricated on RP films, and an analysis of their static and dynamic tuning behavior. The RP film has a ferroelectric-paraelectric phase transition at ˜200 K, and the tunability is strongest at this temperature. The resonators have approximately 2.5% tuning of the resonance frequency at room temperature and 20% tuning at 200 K, and a tuning time scale of less than a nanosecond, which is limited by the measurement circuit rather than material properties., Peer Reviewed, Postprint (author's final draft)

The project aims to study the behaviour of MIM nanostructures using as an insulating material nanoparticles of Al2O3 and TiO2. The work arises from the research carried out by the MNT group of the UPC, that has analyzed the use of SiO2 nanoparticles as a dielectric material, obtaining a supercapacitive behaviour of the MIM structures. Obtained the previous results, it has been decided to follow the same manufacturing process and the same technology, evaporating aluminium to create the electrodes and using electrospray technique in order to deposit the nanoparticles. The results obtained have shown a purely capacitive behaviour of the MIM structures. The phase of the capacitors resulted stable at -90º and the Bode plot shows a straight line with a negative slope. However, the dependence of the capacity with the humidity vary in a important way during the measures. Alumina structures measurements suffer a very varying capacity (varying from 2pF to 500fF), while titania has a greater stability (varying from 100fF to 600fF)., El proyecto que se presenta pretende estudiar el comportamiento de nanoestructuras MIM utilizando como material aislante nanopartículas de Al2O3 i TiO2. El trabajo nace de la investigación que ha llevado a cabo el grup en MNT de la UPC, que ha analizado el uso de nanobolas de SiO2 como dieléctrico, obteniendo un comportamiento supercapacitivo de la estructura MIM. Obtenidos les resultados previos, se ha seguido el mismo proceso de fabricación i la misma tecnología, evaporando aluminio en el porta-objetos i depositando las nanopartículas mediante la técnica d'electrospray. Los resultados demuestran un comportamiento puramente capacitivo de las estructuras fabricadas. La fase de los condensadores resulta estable a -90º i el diagrama de Bode dibuja una recta con pendiente negativo. No obstante, la dependencia de la capacidad con la humedad resulta notoria en las medidas. En l'alúmina se ha medido una capacidad muy inestable entre los diferentes procesos (variando de 2pF a 500fF), en cambio la titánia parece tener una estabilidad mayor (variando de 100fF a 600fF)., El projecte que es presenta pretén estudiar el comportament de nanoestructures MIM emprant com a material aïllant nanopartícules de Al2O3 i TiO2. El treball neix de la recerca feta pel grup en MNT de la UPC que ha analitzat l'ús de nanoboles de SiO2 com a dielèctric, obtenint un comportament supercapacitiu de l'estructura MIM. Obtinguts els resultats previs, s'ha decidit seguir el mateix procés de fabricació i la mateixa tecnologia, evaporant alumini sobre un portaobjectes per crear els electrodes i dipositant les nanopartícules mitjançant la tècnica d'electrospray. Els resultats obtinguts han demostrat un comportament purament capacitiu de les estructures MIM. La fase dels condensador fabricats ha resultat estable a -90º i el diagrama de Bode mostra una recta amb pendent negatiu. Nogensmenys, la dependència de la capacitat amb la humitat es fa notòria en les mesures, variant de manera important el valor de la capacitats. En l'Alúmina s'hi ha mesurat una capacitat molt variant entre diferents processos (des de 2pF a 500fF), en canvi la titania té una estabilitat major (variant de 100fF a 600fF).

Wide-bandgap GaN-based power electronic devices are emerging as promising candidates for the next generation high-efficiency power converters owing to superior material properties such as high electric breakdown field, high electron saturation velocity, and high mobility in a readily available heterojunction 2-dimensional electron gas (2DEG) channel. After a decade of rapid progress in epitaxial growth, device design, processing technology, packaging technology, and gate driving techniques, GaN-on-Si lateral heterojunction power devices are being commercialized and used to implement power converters with impressive efficiency and compact size. However, the highly desirable GaN devices for application with normally-off operation, large gate swing, low gate leakage, small dynamic degradation and high stability and reliability simultaneously, are still under development. In this work, we aimed at solving these challenges with demonstrating a high-quality gate dielectric LPCVD-SiNx at first, then integrating an effective AlN/SiNx passivation layer with the gate dielectric to suppress dynamic on-resistance degradation, and finally, realizing the high-performance normally-off GaN MIS-FET with the highly reliable gate dielectric and effective passivation. The first part of this thesis work is focused on demonstrating the high-quality LPCVD (low pressure chemical vapor deposition)-SiNx gate dielectric, which can suppress the gate leakage effectively and greatly enlarge the gate swing. The SiNx deposited at 780 °C using LPCVD was employed as both gate dielectric and passivation for the GaN-based D-mode MIS-HEMT. The LPCVD-SiNx exhibit desirable gate dielectric performance including small forward and reverse gate leakage and large breakdown electric field. Furthermore, we systematically investigated the gate leakage and breakdown mechanisms of the LPCVD-SiNx thin film deposited on AlGaN/GaN heterostructures. Th

Wide-bandgap GaN-based power electronic devices are emerging as promising candidates for the next generation high-efficiency power converters owing to superior material properties such as high electric breakdown field, high electron saturation velocity, and high mobility in a readily available heterojunction 2-dimensional electron gas (2DEG) channel. After a decade of rapid progress in epitaxial growth, device design, processing technology, packaging technology, and gate driving techniques, GaN-on-Si lateral heterojunction power devices are being commercialized and used to implement power converters with impressive efficiency and compact size. However, the highly desirable GaN devices for application with normally-off operation, large gate swing, low gate leakage, small dynamic degradation and high stability and reliability simultaneously, are still under development. In this work, we aimed at solving these challenges with demonstrating a high-quality gate dielectric LPCVD-SiNx at first, then integrating an effective AlN/SiNx passivation layer with the gate dielectric to suppress dynamic on-resistance degradation, and finally, realizing the high-performance normally-off GaN MIS-FET with the highly reliable gate dielectric and effective passivation. The first part of this thesis work is focused on demonstrating the high-quality LPCVD (low pressure chemical vapor deposition)-SiNx gate dielectric, which can suppress the gate leakage effectively and greatly enlarge the gate swing. The SiNx deposited at 780 °C using LPCVD was employed as both gate dielectric and passivation for the GaN-based D-mode MIS-HEMT. The LPCVD-SiNx exhibit desirable gate dielectric performance including small forward and reverse gate leakage and large breakdown electric field. Furthermore, we systematically investigated the gate leakage and breakdown mechanisms of the LPCVD-SiNx thin film deposited on AlGaN/GaN heterostructures. Th

Microwave absorbers are used in a wide range of applications to eliminate stray or unwanted radiation that could interfere with a system’s operation. For example, the Wireless Avionics Intra-Communications protocol imposed only a minimum shielding effectiveness of only 5dB for the aircraft structural design. It generally consist of a filler material inside a material matrix. The filler consists of one or more type of material that do most of the absorbing. The matrix material is chosen for its physical properties (temperature resistance, weather ability, etc.). This thesis presents the development of a natural oil palm empty fruit bunch fiber (OPEFB)-reinforced polycaprocalctone (PCL) composites with Iron Oxide (Fe2O3) for microwave shielding and absorbing applications. Oil palm empty fruit bunch fiber exhibit excellent mechanical properties when compared with other natural fibers. The OPEFB and PCL are biodegradable, cheap and less dangerous compared to industrial materials. The fillers which is OPEFB and Fe2O3 were prepared by the conventional solid-state method. Different compositions of filler were doped and blended to produce OPEFBPCL and OPEFB-PCL- Fe2O3 composites. The crystalline structure of the composites was analyzed using X-ray diffraction (XRD) machine to ensure the sample only containing the fillers without any contamination while the theoretical calculation of the transmission coefficients of the sample placed in the waveguide was computed using Finite Element Method (FEM) and was accomplished using COMSOL software. The transmission and reflection coefficients as well as dielectric properties were measured using a PNA (N5227) Network Analyzer from 8 GHz to 12 GHz at room temperature by using open ended coaxial (OEC) and rectangular waveguide (RWG) technique. The permittivity of the composites was found to be dependable on the mixing ratio values between OPEFB, PCL, and Fe2O3. Both the dielectric constant and loss factor of the OPEFB-PCL and OPEFB-PCL

This paper presents the circuit topology of a second order sigma-delta control of charge trapping for MOS capacitors. With this new topology it is possible to avoid the presence of plateaus that can be found in first-order sigma-delta modulators. Plateaus are unwanted phenomena in which the control is locked for a certain time interval (of unknown duration). In this case the control output is constant and therefore the controlled device is in fact in open-loop configuration. It is shown that the presence of plateaus is avoided in MOS capacitors using the proposed approach., Peer Reviewed, Postprint (author's final draft)

This TFG is focused on the development of high quality n+ and p+ regions based on laser processed dielectric films. The involved films consist of a thin intrinsic amorphous silicon layer (a-Si:H(i)) capped with a doped (phosphorus for n+ and boron for p+ regions, respectively) amorphous silicon film (a-Si:H(n) or a-Si:H(p)). Finally, a dielectric silicon carbide layer (SiCx) is deposited on top. All these films are deposited by PECVD. This approach has already applied in finished c-Si solar cells for n+ regions with very thin aSi:H(i) in the range of 4-5 nm. Based on this results, this work has two main goals. Firstly, we explore the effects of increasing the thickness of the a-Si:H(i) layer on the surface passivation properties of the stack. As a figure of merit, we will use the effective surface recombination velocity (Seff): the lower the value, the better the passivation quality. The experimental results demonstrate that Seff is reduced to 1-3 cm/s when the a-Si:H(i) layer thickness is increased to 28 nm. Secondly, we develop good quality n + regions to create contacts on n-type c-Si substrates (n+/N) using this thicker a-Si:H(i) layers. The goal is to improve the performance of the n+ regions already developed in MNT group. We deduce a specific contact resistance in the 10-3 -10-4 ·cm2 range, which is an excellent result. Next, we use dummy n+/P junction to determine the optimum laser power which is 910-1160 mW. On the other hand a surface recombination velocity of 8500 cm/s is obtained at the n+ contacts. Despite this value is higher than expected, it still low enough to allow highefficiency solar cells. Finally, we explore the case of p + regions by changing the doping atoms in the intermediate a-Si:H film from phosphorus to boron. This is done by replacing phosphine (PH3) gas by Trimethilboron (TMB, (CH3)3B) gas during the film deposition. These regions create p+/N junctions in the final device. The characterization of test devices lead to an optimum laser, Aquest TFG està enfocat en el desenvolupament de regions n+ i p+ d’alta qualitat basades en capes de dielèctric processades mitjançant làser. Les capes involucrades consten d’una fina capa intrínseca de silici amorf (a-Si:H(i)) coberta amb una capa de silici amorf dopat (amb fòsfor per als n+ i bor per a les regions p+ respectivament) (aSi:H(n) o a-Si:H(p)). Finalment una capa de carbur de silici dielèctric (SiCx ) es diposita al damunt de tot. Totes les capes es generaran per deposició mitjançant PECVD. Aquesta aproximació ja s’ha aplicat per al cas de cèl·lules solars de c-Si per a regions n+ amb una capa molt prima de a-Si:H(i) en un rang de grossor d’entre 4-5 nm. Basant-se en aquests resultats, aquest treball consta de dos objectius principals. En primer lloc, explorar els efectes que té incrementar el grossor de la capa de a-Si:H(i) sobre les propietats de passivació del “stack”. Com a figura de mèrit, s’utilitzarà la velocitat de recombinació efectiva (Seff): com més baix en sigui el valor, millor serà la passivació. Els resultats experiments demostren que Seff es redueix fins a 1-3 cm/s a l’incrementar-se el grossor de la capa de a-Si:H(i) fins a 28 nm. En segon lloc, desenvolupar regions n+ per a crear contactes en substrats de c-Si de tipus n (n+ /N) mitjançant capes de a-Si:H(i) més gruixudes. L’objectiu és millorar les especificacions de les regions n+ prèviament desenvolupades pel grup MNT. S’obté una resistència de contacte específica de en el range de 10-3 -10-4 ·cm2 , el qual es un resultat excel·lent. Seguidament utilitzarem unions n+ /P de prova per a determinar la potència òptima de làser que és de 910-1160 mW. D’altra banda, s’obté una velocitat de recombinació superficial de 8500 cm/s en els contactes n+ . A pesar que aquest valor és més alt de l’esperat, segueix sent suficientment baix com per a permetre cèl·lules solars d’altra eficiència. Finalment, s’explora el cas de regions p+ substituint els àtoms de fòsfor dopants en la capa intermitja, Este TFG está enfocado al desarrollo de regiones n+ y p+ de alta calidad basadas en capas de dieléctrico procesadas mediante laser. Las capas involucradas constan de una fina capa intrínseca de silicio amorfo (a-Si:H(i)) cubierta con una capa de silicio amorfo dopado (con fósforo para los n+ y boro para las regiones p+ respectivamente) (a-Si:H(n) o a-Si:H(p)). Finalmente, una capa de carburo de silicio dieléctrico (SiCx) se deposita en la parte superior de todo. Todas las capas se van a generar por deposición mediante PECVD. Esta aproximación ya se ha aplicado para el caso de células solares de c-Si para regiones n+ con una capa muy delgada de a-Si:H(i) en un rango de grosor de entre 4-5 nm. Basándose en estos resultados, este trabajo consta de dos objetivos principales. En primer lugar, explorar los efectos que tiene incrementar el grosor de la capa de a-Si:H(i) sobre las propiedades de pasivación del “stack”. Como figura de mérito, se va a utilizar la velocidad de recombinación efectiva (Seff): cuanto más bajo sea su valor, mejor va a ser la pasivación. Los resultados experimentados demuestran que Seff se reducen hasta 1-3 cm/s al incrementarse el grosor de la capa de a-Si:H(i) hasta 28 nm. En segundo lugar, desarrollar regiones n+ para crear contactos en sustratos de c-Si de tipo n (n+ /N) mediante capas de a-Si:H(i) más gruesas. El objetivo es mejorar las especificaciones de las regiones n+ previamente desarrolladas por el grupo MNT. Se obtiene una resistencia de contacto específica en el rango de 10-3 -10-4 ·cm2 , el cual es un resultado excelente. Seguidamente se van a utilizar uniones n+ /P de prueba para determinar la potencia optima de laser que es de 910-1160 mW. En paralelo, se obtiene una velocidad de recombinación superficial de 8500 cm/s en los contactos n+ . a pesar de que este valor es más alto de lo esperado, sigue siendo suficientemente bajo como para permitir células solares de alta eficiencia. Finalmente, se explora el caso de regiones p+ sustit

Wide-bandgap GaN-based power electronic devices are emerging as promising candidates for the next generation high-efficiency power converters owing to superior material properties such as high electric breakdown field, high electron saturation velocity, and high mobility in a readily available heterojunction 2-dimensional electron gas (2DEG) channel. After a decade of rapid progress in epitaxial growth, device design, processing technology, packaging technology, and gate driving techniques, GaN-on-Si lateral heterojunction power devices are being commercialized and used to implement power converters with impressive efficiency and compact size. However, the highly desirable GaN devices for application with normally-off operation, large gate swing, low gate leakage, small dynamic degradation and high stability and reliability simultaneously, are still under development. In this work, we aimed at solving these challenges with demonstrating a high-quality gate dielectric LPCVD-SiNx at first, then integrating an effective AlN/SiNx passivation layer with the gate dielectric to suppress dynamic on-resistance degradation, and finally, realizing the high-performance normally-off GaN MIS-FET with the highly reliable gate dielectric and effective passivation. The first part of this thesis work is focused on demonstrating the high-quality LPCVD (low pressure chemical vapor deposition)-SiNx gate dielectric, which can suppress the gate leakage effectively and greatly enlarge the gate swing. The SiNx deposited at 780 °C using LPCVD was employed as both gate dielectric and passivation for the GaN-based D-mode MIS-HEMT. The LPCVD-SiNx exhibit desirable gate dielectric performance including small forward and reverse gate leakage and large breakdown electric field. Furthermore, we systematically investigated the gate leakage and breakdown mechanisms of the LPCVD-SiNx thin film deposited on AlGaN/GaN heterostructures. Th

Microwave absorbers are used in a wide range of applications to eliminate stray or unwanted radiation that could interfere with a system’s operation. For example, the Wireless Avionics Intra-Communications protocol imposed only a minimum shielding effectiveness of only 5dB for the aircraft structural design. It generally consist of a filler material inside a material matrix. The filler consists of one or more type of material that do most of the absorbing. The matrix material is chosen for its physical properties (temperature resistance, weather ability, etc.). This thesis presents the development of a natural oil palm empty fruit bunch fiber (OPEFB)-reinforced polycaprocalctone (PCL) composites with Iron Oxide (Fe2O3) for microwave shielding and absorbing applications. Oil palm empty fruit bunch fiber exhibit excellent mechanical properties when compared with other natural fibers. The OPEFB and PCL are biodegradable, cheap and less dangerous compared to industrial materials. The fillers which is OPEFB and Fe2O3 were prepared by the conventional solid-state method. Different compositions of filler were doped and blended to produce OPEFBPCL and OPEFB-PCL- Fe2O3 composites. The crystalline structure of the composites was analyzed using X-ray diffraction (XRD) machine to ensure the sample only containing the fillers without any contamination while the theoretical calculation of the transmission coefficients of the sample placed in the waveguide was computed using Finite Element Method (FEM) and was accomplished using COMSOL software. The transmission and reflection coefficients as well as dielectric properties were measured using a PNA (N5227) Network Analyzer from 8 GHz to 12 GHz at room temperature by using open ended coaxial (OEC) and rectangular waveguide (RWG) technique. The permittivity of the composites was found to be dependable on the mixing ratio values between OPEFB, PCL, and Fe2O3. Both the dielectric constant and loss factor of the OPEFB-PCL and OPEFB-PCL

Power cables with extruded crosslinked polyethylene (XLPE) insulation are used in HVAC and HVDC applications. These cables usually go through a degassing process to remove the methane formed in XLPE during the cross-linking reactions. In case of HVDC cables, the general belief is that the polar peroxide decomposition products (PDP) content significantly influences the conduction and space charge behavior of XLPE. This belief is mainly based on the results of experiments made on thin XLPE samples with different heat-treatments; but since heat-treatment also influences the morphology of the polymer, it is necessary to consider this effect as well. It is common to use polyethylene terephthalate (PET) film as a protective layer during sample press molding. Studies on the influence of the pressing film on the electrical properties of the sample are rare. In this work, the results of a series of experiments performed on 0.5 mm thick XLPE plaque samples in reference to additive free LDPE samples with different heat-treatment times are presented. Beside the PDP content, the morphology, DC conductivity and polarization properties are studied and analyzed. It was found that the pressing film used during sample preparation has a significant effect on the results and if not corrected, it may lead to wrong conclusions about the influence of the PDP content. Eliminating the effect of the pressing film, no clear correlation between the DC conductivity, dielectric loss and the PDP content was observed. The relation between the PDP content and DC conductivity is not found to be obvious, hence this correlation may need to be further evaluated., QC 20170217

The increasing concerns on environmental issues have led to the introduction of vegetable oils such as Palm Oil (PO) and Coconut Oil (CO) as potential candidates for alternative dielectric insulating fluids for mineral oil. Even though the overall performances of these oils are comparable with other types of vegetable oils, some improvements can be carried out especially on their electrical properties. Extensive electrical examinations need to be conducted on these PO and CO at laboratory level in order to determine its feasibility for practical application in transformers. This work presents an examination on the electrical properties of PO and CO under the presence of a semi-conductive nanoparticle, Titanium (IV) Oxide (TiO2). Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein was used in this study, whereas the volume concentrations of TiO2 used are from 0.001% to 0.050%. Investigation on the effects of a surfactant, Cetrimonium Bromide (CTAB) was also carried out. Transmission Electron Microscope (TEM) was used to examine the morphology of RBDPO and CO based TiO2 nanofluid. Moreover, AC and lightning breakdown voltages, dielectric dissipation factor, relative permittivity and resistivity measurements were taken whereas the withstand voltages for AC and lightning were statistically evaluated through Weibull distribution. This study found that the AC breakdown voltages of the RBDPO and CO can be increased through introduction of TiO2 without CTAB where the highest percentages of increments are 17.2% and 22.7% respectively. The AC breakdown voltage of RBDPO and CO based TiO2 nanofluid can however decrease with introduction of CTAB. The effect of TiO2 on the lightning breakdown voltages of RBDPO and CO under both fields is quite small for samples with or without CTAB where the highest percentages of increments are 9.2% and 11.3% respectively. The dielectric dissipation factors and resistivity of RBDPO and CO based TiO2 nanofluid are significantly affected by th

Graphene is a unique material for the implementation of terahertz antennas due to extraordinary properties of the resulting devices, such as tunability and compactness. Existing graphene antennas are based on pure plasmonic structures, which are compact but show moderate to high losses. To achieve higher efficiency with low cost, one can apply the theory behind dielectric resonator antennas widely used in millimeter-wave systems. This paper presents the concept of hybridization of surface plasmon and dielectric wave modes. Radiation efficiency, reconfigurability, and miniaturization of antennas built upon this principle are qualitatively discussed and compared with those of pure plasmonic antennas. To this end, a quantitative study of pure and hybrid plas-monic one-dimensional guided-wave structures is performed. The results show that hybrid structures can be employed to design terahertz antennas with high radiation efficiency and gain, moderate miniaturization, and tunability, while terahertz antennas based on pure plasmonic structures can provide high miniaturization and tunability yet with low radiation efficiency and gain., Peer Reviewed, Postprint (published version)

An X-band radiator as an open-ended waveguide with a hybrid dielectric insert is proposed. The insert is in the form of a parallelepiped, which fills the entire cross section of the waveguide and constitutes a Teflon matrix with local inhomogeneities in the form of dielectric cylinders with a different permittivity. The design allows for forming various near-field distributions and, hence, the radiator performance by means of definite combinations of the local inhomogeneities can be modified. A number of configurations in the location of air and quartz cylinders are investigated. The calculated and experimental results are in good agreement. The proposed approach to the near-field formation of the aperture antenna is promising, because the variety of possible configurations in the location of local inhomogeneities with different permittivity provides new opportunities in terms of designing both single radiators and antenna arrays.

The increasing concerns on environmental issues have led to the introduction of vegetable oils such as Palm Oil (PO) and Coconut Oil (CO) as potential candidates for alternative dielectric insulating fluids for mineral oil. Even though the overall performances of these oils are comparable with other types of vegetable oils, some improvements can be carried out especially on their electrical properties. Extensive electrical examinations need to be conducted on these PO and CO at laboratory level in order to determine its feasibility for practical application in transformers. This work presents an examination on the electrical properties of PO and CO under the presence of a semi-conductive nanoparticle, Titanium (IV) Oxide (TiO2). Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein was used in this study, whereas the volume concentrations of TiO2 used are from 0.001% to 0.050%. Investigation on the effects of a surfactant, Cetrimonium Bromide (CTAB) was also carried out. Transmission Electron Microscope (TEM) was used to examine the morphology of RBDPO and CO based TiO2 nanofluid. Moreover, AC and lightning breakdown voltages, dielectric dissipation factor, relative permittivity and resistivity measurements were taken whereas the withstand voltages for AC and lightning were statistically evaluated through Weibull distribution. This study found that the AC breakdown voltages of the RBDPO and CO can be increased through introduction of TiO2 without CTAB where the highest percentages of increments are 17.2% and 22.7% respectively. The AC breakdown voltage of RBDPO and CO based TiO2 nanofluid can however decrease with introduction of CTAB. The effect of TiO2 on the lightning breakdown voltages of RBDPO and CO under both fields is quite small for samples with or without CTAB where the highest percentages of increments are 9.2% and 11.3% respectively. The dielectric dissipation factors and resistivity of RBDPO and CO based TiO2 nanofluid are significantly affected by th

Thesis (Elec.E)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982., MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING, Includes bibliographical references., by Huan Lim Lee., Elec.E

Thesis (Elec.E)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982., MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING, Includes bibliographical references., by Huan Lim Lee., Elec.E

The Light Airborne Reflectometer for GNSS-R Observations (LARGO) is an airborne instrument designed for measuring the coherent reflectivity from different soils. In this work, an improved version of LARGO has been used in a field campaign together with other conventional remote sensing instruments. All the corrections made to the raw coherent reflectivity including the antenna pattern compensation, and a topographic correction are presented. The correlation between corrected coherent reflectivity and in situ soil moisture was not high enough due to the dry conditions of the field campaign., Peer Reviewed, Postprint (published version)

Ba(6-3x)Nd(8+2x)Ti(18)O(54) (BNTl14) is a high permittivity dielectric with low temperature coefficient (Tcf). Low coefficient of change of dielectric permittivity with temperature (Tcf) is an unusual materials property. The research is aimed at discovering how atomic structure relates to temperature coefficient. Sub-Ångström scanning transmission electron microscopy (STEM) is used to measure mixed occupancy of Nd and Ba in atomic columns. It was expected that phase separation would occur to accommodate mixing of dissimilar ions. However no evidence of phase separation was found. There is a good image match between experiment and high angle annular dark field (HAADF) simulation. Vacancies and excess Ba ions appear to be randomly arranged on the available sites which would result in distortion of TiO6 octahedra. The low Tcf may arise from TiO6 distortion.

Electronics advancement demands integration of large number of transistors /capacitors in a very small chip area. Thus, small feature size fabrication is a critical issue and precise fabrications of features under nano scale require advanced lithographic and etching techniques. In this paper, MOS capacitor with TiN metal-gate and HfO2 dielectric layer was fabricated in a world class clean-room lab in KTH. There, state-of-the art lithography stepper, advanced etching machines and all important clean-room fabrication facilities were used for successful fabrication of the nano-dimension MOS capacitor, whose detailed experimental procedures and results are exhaustively dealt in this report., QC 20130801

“© 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”, In this paper, a full-wave method for the electromagnetic analysis of dielectric-loaded cylindrical and coaxial waveguides and cavities is developed. For this purpose, a new four-port ring network is proposed, and the mode-matching method is applied to calculate the generalized admittance matrix of this new structure. A number of analyses on dielectric-loaded waveguide structures and cavities have been conducted in order to validate and to assess the accuracy of the new approach. The results have been compared with theoretical values, numerical modeling from the literature, and data from commercial electromagnetic simulators. The method has been also applied to the accurate determination of dielectric properties, and we provide an example of these measurements as another way to validate this new method. © 1963-2012 IEEE.

Desde principios de la década de los noventa se han desarrollado líquidos dieléctricos de origen vegetal que tienen como principales ventajas las mejoras de los limitantes presentes en los aceites derivados del petróleo. Son fluidos sumamente biodegradables y tienen un alto punto de inflamación; sin embargo, su elevado costo y su no muy amplia evaluación en servicio (desempeño), dado su relativo poco tiempo de uso, han limitado su aplicación. En el presente trabajo se presenta una revisión del estado de la técnica de los aceites dieléctricos de origen vegetal para uso en transformadores. Se muestra un repaso de su evolución desde sus inicios hasta la actualidad., Since the early 1990s, dielectric fluids have been developed from plants. The use of plants has the main advantage of improving the limitations of petroleum oils. Plant fluids are highly biodegradable and have a high flash point; but their high cost and their not-very-wide in-service evaluation (performance), because of its relatively short time of use, have limited their application. This study reviews the state of the art of dielectric oils of plant origin to be used in transformers, including an overview of their evolution from their origin until today., Desde princípios da década dos noventa foram desenvolvidos líquidos dielétricos de origem vegetal que têm como principais vantagens as melhoras dos limitantes presentes nos óleos derivados do petróleo. São fluidos extremamente biodegradáveis e têm um alto ponto de inflamação; porém, seu elevado custo e sua não muito amplia avaliação em serviço (desempenho), dado seu relativo pouco tempo de uso, tem limitado sua aplicação. No presente trabalho apresenta-se una revisão do estado da técnica dos óleos dielétricos de origem vegetal para uso em transformadores. Mostra-se um percurso de sua evolução desde seus inícios até a atualidade.

An inverse scattering approach based on the field equivalence principle is developed for reconstructing the parameters of the medium of a scattering object. A problem equivalent to the original scattering problem but internal to the measurement surface is set up. The equivalent surface currents determined by the measured total-field data rigorously yield the incident fields in the region under test, so the approach does not require explicit knowledge of the incident fields. Taking into account the fact that the equivalent surface currents produce a null field external to the surface, a functional of the medium's parameters is introduced, and a genetic algorithm is applied to minimization of the functional. Numerical simulations for imaging defects in a known dielectric cylinder from only total-field data measured on an observation surface are performed to illustrate the efficacy of the proposed inversion method., Optics Letters, 37(16), pp.3432-3434; 2012

Desde principios de la década de los noventa se han desarrollado líquidos dieléctricos de origen vegetal que tienen como principales ventajas las mejoras de los limitantes presentes en los aceites derivados del petróleo. Son fluidos sumamente biodegradables y tienen un alto punto de inflamación; sin embargo, su elevado costo y su no muy amplia evaluación en servicio (desempeño), dado su relativo poco tiempo de uso, han limitado su aplicación. En el presente trabajo se presenta una revisión del estado de la técnica de los aceites dieléctricos de origen vegetal para uso en transformadores. Se muestra un repaso de su evolución desde sus inicios hasta la actualidad., Since the early 1990s, dielectric fluids have been developed from plants. The use of plants has the main advantage of improving the limitations of petroleum oils. Plant fluids are highly biodegradable and have a high flash point; but their high cost and their not-very-wide in-service evaluation (performance), because of its relatively short time of use, have limited their application. This study reviews the state of the art of dielectric oils of plant origin to be used in transformers, including an overview of their evolution from their origin until today., Desde princípios da década dos noventa foram desenvolvidos líquidos dielétricos de origem vegetal que têm como principais vantagens as melhoras dos limitantes presentes nos óleos derivados do petróleo. São fluidos extremamente biodegradáveis e têm um alto ponto de inflamação; porém, seu elevado custo e sua não muito amplia avaliação em serviço (desempenho), dado seu relativo pouco tempo de uso, tem limitado sua aplicação. No presente trabalho apresenta-se una revisão do estado da técnica dos óleos dielétricos de origem vegetal para uso em transformadores. Mostra-se um percurso de sua evolução desde seus inícios até a atualidade.

Seminar given by Associate Professor Iain Anderson, Auckland Bioengineering Institute and Department of Engineering Science., The Biomimetics Lab, which I co-founded about 7 years ago, is developing soft machines - devices that are inspired by nature. For inspiration we are looking to ctenophores and jellyfish, which are amongst the most ancient of animals. They do not have brains yet are capable of performing complex tasks associated with swimming and prey capture. Ctenophore swimming is facilitated through the simple and effective sequential triggering of mechano-sensitive cilia paddles. For the jellyfish, swimming is associated with orderly rhythmic contractions of the bell controlled by pacemaker mechanisms. These creatures have fully integrated self-sensing and control. We are building proof-of-concept soft machines with self-sensing and integrated control using multi-functional Dielectric Elastomer (DE) devices. Renowned for their muscle-like performance, DE actuators can be made strain-sensitive through capacitive feedback. A Biomimetics Lab invention, the DE switch now enables fully integrated power control and soft logic within a more complex DE device. Thus the development of soft autonomous machines that emulate key aspects of jellyfish control is possible. I will describe some examples from the lab that include a soft motor, conveyor, and an oscillator. For my inaugural talk as an Associate Professor I shall also describe how I came to this project. This has involved a few life-changing moments. On a summer’s day in 1969 I had one of these moments. I could not put it better than Jacques Cousteau: “Sometimes we are lucky enough to know that our lives have been changed … It happened to me that summers’ day when my eyes opened to the world beneath the surface of the sea.” [A. Madsen, Cousteau- an unauthorized biography. Redwood Burn Ltd., Trowbridge, Wiltshire, 1986]

[EN] Nanocomposite materials obtained from natural rubber (NR) reinforced with different amounts of cellulose II nanoparticles (in the range of 0 to 30 phr) are studied by dielectric spectroscopy (DS). For comparative purposes the pure materials, NR and cellulose, are also investigated. The dielectric spectra of the nanocomposites exhibit: (a) two overlapped ¿-relaxations associated respectively with the dynamic glass transitions of NR (faster process) and of the lipid present in NR; (b) a ß-relaxation associated with local chain dynamics of cellulose and (c) a relaxation process associated to the presence of traces of water in cellulose. The spectra exhibit conductivity phenomena at low frequencies and high temperatures. The samples were also studied in the dry state. An explanation is given concerning the cellulose effect on the dielectric properties of the dry and wet nanocomposites. © 2010 Elsevier B.V.All rights reserved.

[EN] Dielectric spectroscopy studies have been performed on fresh and osmotically dehydrated kiwifruits (Actinidia deliciosa cv Hayward). The osmotic treatment consisted on the immersion the samples into 65% (w/w) sucrose aqueous solution at 30 °C during different treatment times from 5 to 1440 min. Some physical-chemical parameters were measured in fresh, treated and reposed (24 h at 30 °C) samples. Dielectric spectra were measured in the frequency range from 500 MHz to 20 GHz by an Agilent 85070E Open-ended Coaxial Probe connected to an Agilent E8362B Vector Network Analyzer in the fresh, treated and reposed samples. It has been demonstrated that the dielectric technique is a good method to control the osmotic treatment in kiwifruit. Industrial relevance: The results of this research article are demonstrated to be useful for controlling candying of kiwifruits in bakery industries. Thus, the industrial relevance is clear in order to optimize the osmotic dehydration times and the final quantity of sugars added by using a non destructive technique that can be implemented in process line. Dielectric spectroscopy, which can be considered an emerging technology, has the advantage of being an objective and a rapid technique. For all these reasons we are sending to this journal "Innovative Food Science and Emerging Technologies" our results. © 2011 Elsevier Ltd. All rights reserved.

[EN] Dielectric measurements of different standard solutions (nucleotides, nucleosides, lactic acid and myoglobin) were assayed simulating the concentrations of these substances in early postmortem meat. These assays were performed for considering the potential use of dielectric spectra for the quality control of meat. Good correlations among solutions of Adenosine Triphosphate (ATP), Inosine Monophosphate (IMP) and lactic acid with loss factor at punctual frequencies (0.5, 0.915 and 1 GHz) were found. The other assayed substances did not present a marked effect over the electromagnetic spectra. Good correlations of dielectric properties with IMP and lactic acid content of real pork meat samples were also found at 0.5 GHz. This work is presenting prospective data of dielectric spectra for certain key biochemical markers in order to consider its potential application as a non-destructive control sensor for the prediction of pork meat quality. (C) 2010 Elsevier Ltd. All rights reserved.

[EN] Dielectric spectroscopy studies have been performed on fresh and osmotically dehydrated Granny Smith apples. The osmotic treatment consisted on immerse the samples into 65% (w/w) sucrose aqueous solution at 30 degrees C during different exposure times lasted from 3 h to 16 days. Some physical chemical parameters were measured in fresh, treated and reposed (24 h at 30 degrees C) samples. Dielectric spectra were measured in the frequency range from 500 MHz to 20 GHz by an Agilent 85070E Open-ended Coaxial Probe connected to an Agilent E8362B Vector Network Analyzer in the fresh, treated and reposed samples. It has been demonstrated that the dielectric properties are a good tool to control the surface water activity by using the loss factor at relaxation frequency. This relation of dielectric properties with the water activity allows controlling the shrinkage level and determines the moment when the driving forces change from diffusional to mechanical behaviors. This value corresponds to 12.25 +/- 0.16 and represents a practical control value to decide if the final dehydrated samples shrink or swell. Moreover, the quantity of adsorbed water was estimated by the subtraction between the overall moisture and the water content in liquid phase estimated by using dielectric loss factor at relaxation frequency. (C) 2010 Elsevier Ltd. All rights reserved.

[EN] Dielectric spectroscopy studies have been performed on fresh and osmotically dehydrated Granny Smith apples. The osmotic treatment consisted on immerse the samples into 65% (w/w) sucrose aqueous solution at 30 degrees C during different exposure times lasted from 3 h to 16 days. Some physical chemical parameters were measured in fresh, treated and reposed (24 h at 30 degrees C) samples. Dielectric spectra were measured in the frequency range from 500 MHz to 20 GHz by an Agilent 85070E Open-ended Coaxial Probe connected to an Agilent E8362B Vector Network Analyzer in the fresh, treated and reposed samples. It has been demonstrated that the dielectric properties are a good tool to control the surface water activity by using the loss factor at relaxation frequency. This relation of dielectric properties with the water activity allows controlling the shrinkage level and determines the moment when the driving forces change from diffusional to mechanical behaviors. This value corresponds to 12.25 +/- 0.16 and represents a practical control value to decide if the final dehydrated samples shrink or swell. Moreover, the quantity of adsorbed water was estimated by the subtraction between the overall moisture and the water content in liquid phase estimated by using dielectric loss factor at relaxation frequency. (C) 2010 Elsevier Ltd. All rights reserved.

[EN] Nanocomposite materials obtained from natural rubber (NR) reinforced with different amounts of cellulose II nanoparticles (in the range of 0 to 30 phr) are studied by dielectric spectroscopy (DS). For comparative purposes the pure materials, NR and cellulose, are also investigated. The dielectric spectra of the nanocomposites exhibit: (a) two overlapped ¿-relaxations associated respectively with the dynamic glass transitions of NR (faster process) and of the lipid present in NR; (b) a ß-relaxation associated with local chain dynamics of cellulose and (c) a relaxation process associated to the presence of traces of water in cellulose. The spectra exhibit conductivity phenomena at low frequencies and high temperatures. The samples were also studied in the dry state. An explanation is given concerning the cellulose effect on the dielectric properties of the dry and wet nanocomposites. © 2010 Elsevier B.V.All rights reserved.

[EN] Dielectric spectroscopy studies have been performed on fresh and osmotically dehydrated kiwifruits (Actinidia deliciosa cv Hayward). The osmotic treatment consisted on the immersion the samples into 65% (w/w) sucrose aqueous solution at 30 °C during different treatment times from 5 to 1440 min. Some physical-chemical parameters were measured in fresh, treated and reposed (24 h at 30 °C) samples. Dielectric spectra were measured in the frequency range from 500 MHz to 20 GHz by an Agilent 85070E Open-ended Coaxial Probe connected to an Agilent E8362B Vector Network Analyzer in the fresh, treated and reposed samples. It has been demonstrated that the dielectric technique is a good method to control the osmotic treatment in kiwifruit. Industrial relevance: The results of this research article are demonstrated to be useful for controlling candying of kiwifruits in bakery industries. Thus, the industrial relevance is clear in order to optimize the osmotic dehydration times and the final quantity of sugars added by using a non destructive technique that can be implemented in process line. Dielectric spectroscopy, which can be considered an emerging technology, has the advantage of being an objective and a rapid technique. For all these reasons we are sending to this journal "Innovative Food Science and Emerging Technologies" our results. © 2011 Elsevier Ltd. All rights reserved.

[EN] Dielectric measurements of different standard solutions (nucleotides, nucleosides, lactic acid and myoglobin) were assayed simulating the concentrations of these substances in early postmortem meat. These assays were performed for considering the potential use of dielectric spectra for the quality control of meat. Good correlations among solutions of Adenosine Triphosphate (ATP), Inosine Monophosphate (IMP) and lactic acid with loss factor at punctual frequencies (0.5, 0.915 and 1 GHz) were found. The other assayed substances did not present a marked effect over the electromagnetic spectra. Good correlations of dielectric properties with IMP and lactic acid content of real pork meat samples were also found at 0.5 GHz. This work is presenting prospective data of dielectric spectra for certain key biochemical markers in order to consider its potential application as a non-destructive control sensor for the prediction of pork meat quality. (C) 2010 Elsevier Ltd. All rights reserved.

Ionic conductivity, diffusion coefficients, mobility and ionic concentration for lithium salts dissolved in polymer electrolytes are determined by the modeling of the dielectric loss and spectra. Cation and anion diffusion coefficients are quantified using the Trukhan model depending on the assumed ratio of the cation to anion diffusion coefficients. Measurements are performed for polymer electrolytes consisting of polyethylene oxide (PEO) with dissolved LiClO 4 salts for different sample thicknesses and temperatures ranging from 5 to 105 °C, which comprises both the crystalline and amorphous phases of the composite electrolyte. A good phenomenological description of the dielectric loss spectra is obtained for both the semi-crystalline and amorphous phases. The fraction of mobile ions is estimated to vary from 0.002% at 25 °C (semi-crystalline phase) up to 0.05% at 80 °C (amorphous phase).